Geological model for oil gravity variations in Oriente Basin, Ecuador
Conference
·
OSTI ID:6636734
The Oriente basin is one of the major productive Subandean basins. Most of the fields produce 29/sup 0/-33/sup 0/ API paraffinic oils, but oils have been discovered with gravities ranging from 10/sup 0/to 35/sup 0/ API. All the oils have been recovered from multiple middle to Late Cretaceous sandstone reservoirs (Hollin and Napo Formations). Wells display a variety of oil gravities by reservoir. The origin of the Oriente oils is problematical and controversial, but structural, geochemical, and well evidence suggest a vast oil kitchen west of the present Andean foothills that was mature for oil generation by at least early Tertiary. Oil analyses indicate a single family of oils is present. Oil gravity variations can be explained systematically in terms of the various alteration processes suffered by the oil in each reservoir. Intermittent early Andean uplift (latest Cretaceous to Mid-Eocene) resulted in biodegradation and water-washing of oils, particularly in the uppermost Napo reservoirs. The main Andean orogeny (Pliocene) uplifted the Hollin reservoir to outcrop in the west, and tilted the basin down to the south. This movement resulted in water washing or flushing of the Hollin aquifer and a phase of northward remigration of oil. Late Andean structures postdated primary oil migration. Almost all structures displaying growth during the Late Cretaceous to early Eocene have been oil bearing, but some, particularly those located on the present-day basin flanks, were later severely biodegraded or breached.
- OSTI ID:
- 6636734
- Report Number(s):
- CONF-880301-
- Country of Publication:
- United States
- Language:
- English
Similar Records
Petroleum systems along the foldbelt associated to the Maranon-Oriente-Putomayo Foreland Basins
Mesozoic and cenozoic tectonic evolution of the Maranon Basin in Southeastern Columbia, Eastern Ecuador and Northeastern Peru
The 1-AB block fields-a giant oil accumulation in Eastern Peru
Journal Article
·
Thu Aug 01 00:00:00 EDT 1996
· AAPG Bulletin
·
OSTI ID:421138
Mesozoic and cenozoic tectonic evolution of the Maranon Basin in Southeastern Columbia, Eastern Ecuador and Northeastern Peru
Conference
·
Sun Jan 31 23:00:00 EST 1993
· AAPG Bulletin (American Association of Petroleum Geologists); (United States)
·
OSTI ID:5940205
The 1-AB block fields-a giant oil accumulation in Eastern Peru
Conference
·
Sun Jan 31 23:00:00 EST 1993
· AAPG Bulletin (American Association of Petroleum Geologists); (United States)
·
OSTI ID:6105024
Related Subjects
02 PETROLEUM
020200 -- Petroleum-- Reserves
Geology
& Exploration
023000* -- Petroleum-- Properties & Composition
ALKANES
API GRAVITY
CHEMISTRY
CRETACEOUS PERIOD
DENSITY
DEVELOPING COUNTRIES
ECUADOR
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
HYDROCARBONS
LATIN AMERICA
MASS TRANSFER
MESOZOIC ERA
MINERAL RESOURCES
ORGANIC COMPOUNDS
PETROLEUM
PETROLEUM DEPOSITS
PHYSICAL PROPERTIES
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SOUTH AMERICA
020200 -- Petroleum-- Reserves
Geology
& Exploration
023000* -- Petroleum-- Properties & Composition
ALKANES
API GRAVITY
CHEMISTRY
CRETACEOUS PERIOD
DENSITY
DEVELOPING COUNTRIES
ECUADOR
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
HYDROCARBONS
LATIN AMERICA
MASS TRANSFER
MESOZOIC ERA
MINERAL RESOURCES
ORGANIC COMPOUNDS
PETROLEUM
PETROLEUM DEPOSITS
PHYSICAL PROPERTIES
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SOUTH AMERICA